Lower unit oil under extreme pressure

[crankit]

After my last trip, I noticed my prop had become fairly hard to turn. I opened the lower unit fill screw and air was hissing out causing the oil to bubble. I have never seen this before when changing the lower unit oil. When the screw was fully removed, the oil shot out quickly. After releiving the pressure, the prop turned freely like normal. The oil looked pretty good, not extremely milkly, just about what it normally looks like. Any ideas on what this could be?

Thanks,

Crankit

 

[crankit]

Re: Lower unit oil under extreme pressure

Forgot to add that the oil had a stronger odor than normal.

 

[crankit]

Re: Lower unit oil under extreme pressure

ttt

 

[F_R]

Re: Lower unit oil under extreme pressure

I've seen that happen before. Stinky oil under pressure, right? Can only blame it on the wrong kind of oil until somebody corrects me. Drain it out and refill with a good brand of outboard gear oil. In fact, I probably would first fill it with mineral spirits to rinse it out, and drain that out (don't run it with mineral spirits).

 

[crankit]

Re: Lower unit oil under extreme pressure

Thanks F R, I've been using the quicksilver gear oil. It's a 1994 175 Johnson Faststrike. Would it be better to use the Johnson/Evinrude brand?

 

[LubeDude]

Re: Lower unit oil under extreme pressure

Probably not a "Type of oil problem"! Are you sure that it was not overfilled last time? If over filled this can happen. Also, if the boat was in the sun and the lower unit was hot from being in the sun the same thing can happen!

 

[F_R]

Re: Lower unit oil under extreme pressure

Nope, I can't blame the Quicksilver oil.

 

[ezeke]

Re: Lower unit oil under extreme pressure

It's important to add the oil from the bottom fill hole and to stop when the oil runs out the vent hole at the top. If you add more than that, you risk forcing out the seals.